It has been shown that exfoliated bladder cells obtained from the urines of rats fed N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) for sufficient periods to produce bladder cancer contained significantly increased amounts of the enzyme galactosyl transferase. See Plotkin, G. M., Brigham, S. C., Wolf, G., Jacobs, J. B. and Arai, M., "Uridine 5'-diphosphate galactose:glycoprotein galactosyl transferase activity in exfoliated bladder epithelial cells in rats fed N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide", Cancer Biochem. Biophys., 1977, Vol. 2., pp 59-63. Exfoliated bladder cells obtained from rats similarly treated for much shorter periods of time which were insufficient to cause bladder cancer did not show the significant increase in galactosyl transferase.
Based upon this discovery that the level of a specific enzyme, galactosyl transferase, was significantly different in exfoliated cells from tissue containing cancerous cells than the level in comparable cells from normal tissue, an enzymatic noninvasive test for cancer in mammalian tissue was developed. This test is described in U.S. Pat. No. 4,132,600 issued to Plotkin et al. In the method described therein, exfoliated cells from tissue to be tested and assayed for the level of galactosyl transferase activity are incubated with an exogenous galactose acceptor, such as a modified glycoprotein, and a galactose-containing substrate, such as a nucleotide galactose sugar. The amount of galactose transferred by the enzyme in a given time under standard conditions to the acceptor can then be determined and is a measure of the level of galactosyl transferase activity present. If the activity is significantly different from normal values, the organ is likely to contain cancerous tissue.
The enzymatic noninvasive method for detecting cancer described in the Plotkin et al. patent has proven to be highly reliable. It would be an advantage, nevertheless, to have a more rapid, direct and/or inexpensive technique for detecting altered levels of galactosyl transferase.